Seeinstructions): Biodemography is grounded in discoveries of commonalities across species in population characteristics like age-specific hazard functions. Relevance to human aging is largely mediated by mathematical models which link commonalities to fundamental evolutionary processes. We build on a breakthrough from the initial project cycle which led to fully non-linear demographically flexible models for genetic mutation accumulation. In this project, we combine these models for mutational load with the other two main strands of evolutionary life-course modeling, Markov processes for changing individual-level vitality and optimal life history models for genetic and behavioral tradeoffs. We determine the extent to which observed commonalities across species can be interpreted as generic predictions from these integrated models. To inform our modeling, we undertake analysis of two kinds of empirical data, behavioral markers of aging in Mediterranean fruit flies collected by Program Principal Investigator James Carey and experimental data bearing on age-specific signatures of mutational effects in Drosophila melanogaster, collected by Adam Chippindale of University of Oxford through the technique of hemiclonal analysis. We extend our theoretical approach with consideration of costs and constraints on reparability and with models for processes of damage segregation. RELEVANCE (Seeinstructions): Project 3 develops a modeling framework for synthesizing results from the other projects of the program and subsuming them into the broad themes of evolutionary theories of senescence. Patterns of aging in the wild, early-life influences on late-life mortality, ecological variability in stage-dependent population dynamics, sociality and investment in physiological capital all inform the components of our proposed combined models. As they elucidate the population-level implications for age-specific mortality, vitality, and lifespan, the models should help guide continuing experiments and data collection across the program as a whole.